Diphenylethylene butyllithium adduct

Diphenylmethyllithium [881-42-5] can be prepared by the metalation reaction of butyllithium with diphenylmethane in addition, the adduct of butyllithium and 1,1-diphenylethylene is conveniendy prepared in either hydrocarbon or polar solvents such as THF as shown in equation 18. 

Further evidence for the quantitative addition of poly(styryl)lithium with a stoichiometric amount of 1,1-diphenylethylene can be deduced by HNMR analysis of the adduct formed after methanol termination. A characteristic peak (multiplet) at 5 3.5 ppm is observed by HNMR for the terminal methine hydrogen at the chain end in the PS-DPE and no corresponding peak is observed in the base polystyrene. Integration of the area of this peak relative to the area of the resonances corresponding to the methyl protons of the sec-butyllithium initiator fragment at 5 0.5-0.78 ppm gave a value of 1 5.9, in close... 

Nakahama and coworkers [171-173] have developed the bis(4,4 -trimethylsi-lyl)-substituted 1,1-diphenylethylene, 51, to generate the corresponding functional initiators which were used to determine the molecular weights of the resultant polymers by NMR spectroscopy. For example, the polymerization of 4-cyanostyrene was initiated with the adduct of 51 with butyllithium (52), as well as the dipotassium dimer of 51 (54, Eq. 37),... 

Diphenylethylene and -butyllithium combine to afford the 1 1 adduct 149 rapidly and quantitatively. In contrast, the exposure of styrene to -butyllithium unleashes polymerization. This time the rate of the chain growth surpasses that of the 1-phenylhexyllithium (adduct 148) forming initiation step (Scheme 1-108). ... 

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